I just inherited a 96 Disco from my dad. It sat for about a year due to a flex plate/torque conv problem. It has recently been fixed and so my dad gave it to me. I put a can of sea foam in it to clear out the fuel system, not realizing how low the fuel was. It ran super rich with sea foam for about a mile (and ran like garbage for that mile) and has since had a pretty serious issue. It starts right up and idles just fine. Once in gear it drive fine up until about 15 mph. At that point it starts sputtering and missing every now and then (throws a code for random misfire - p0300). By the time I hit 3rd gear and about 30 mph, it runs terribly and will not let me get above 2000 rpm. I will have my foot steady on the gas and it will all of a sudden cut out as if I let my foot off the gas (but i never did). I have to let off the gas and the push the gas again for it to get fuel to the engine... then it cuts out again.

I have replaced all spark plugs and the fuel filter. I am also running 91 octane.

This is brutal and I would appreciate any help I could get.

 

Checked fuel pressure at the rail? Bad fuel pump?

You had the flex plate replaced? There is a ring between it and the crankshaft for the crank sensor, slight damage to it is bad for crank sensor reading/spark

TPS can cause this and mass air flow

 

Time to spend that sixty bucks on an Ultragauge if you haven't already, a much better deal in the long run than hunt n peck sensor replacement

 

Yes an obd2 scanner with live data may be needed but check the other things cause I don't think sea foam would cause random misfires, the crank sensor ring messed up will

 

Just for chuckles try unplugging the MAF and see if there is any appreciable difference one way or the other

 

I had O'reilly clear and rescan the codes again. Multiple codes for cylinder misfire, including a camshaft position sensor code. Is the camshaft position sensor inegrated with the crank sensor ring?

 

Cam sensor is on front below water pump I believe

 

How can I access the crank sensor ring to check for damage? Is there an inspection cover of do I need to pull the oil pan?

 

I know I read someone did but I have not done it, removing oil pan will not help

Remove sensor and turn engine over looking through the hole ?
Or remove the front tin inspection cover front of trans? Or is it like a ford and does not come off?

If bent a little can cause big problem

 

stefanwlsn ... electronic ignition in the 96 year means 4 major points of failure. Crank Angle Sensor (TDC), Cam Position Sensor, the TPS and ICM talks to the computer. Being as though the flex plate and torque convertor was "disturbed" I would personally go right for the crank angle sensor and very that it is properly seated and bolted in. Crank Sensor located drivers side and top of Bell Housing of the transmission.

Intermittent misfire sounds or rather translates to me intermittent ignition caused by the sensor that talks to the ignition control module or ECM telling the coils when to fire. Hens timing and ignition issues will hide behind symptoms of running out of fuel or having just enough fuel to keep running but not adequate supply whel called upon by pushing the gas peddle telling the Throttle Position Sensor how much air to call for in concert with the Mass Air Flow Sensor MAF hiding behind the O2 sensor's signal reading that the thing is running rich... not burning fuel or lean....not enough fuel so stop leaking air into the intake manifold to the stepping motor IAC Idle Air Control....

So.... You see how many issues one sensor causes a chicken to run around the yard with his head cut off?

Crank Angle Sensor..

My bet is that you have ample PSI at the fuel rail but ignition is lacking so it acts like it is starving for GAS. If you get the tire gague from auto zone that has the rubber tire around the gauge and the button on it, use that on the shrader valve and veryfy PSI in a pinch. Gas will not harm the gauge.

Any one else?